Even successful rock and roll bands have a hard time lasting 20 years. For a group to do so when they've been outlawed for 17 of those 20 years is a minor miracle. Which explains why the fans crowded into Manhattan's Performance Space 122 recently gave the Czech band Pulnoc an exuberant ovation before they'd played a lick. The group is a reconstituted version of Eastern Europe's most famous underground band, the Plastic People of the Universe, which was formed in 1968, banned by the government in 1971, jailed in 1976 and harassed throughout its furtive musical career. "There's probably no rock band in the world that has put up with such physical and psychological abuse," says Tim Ryback, author of an upcoming book about Soviet-bloc rock. "They were extremely significant as a symbol of resistance."

They may look and sound like any other hard rockers, in their black leather and Ray-Bans, but from the beginning the Plastic People have lived a history filled with Kafkaesque ironies. For instance, the band never actually performed at its most legendary concert in March 1974. Hundreds of young Czech rock fans converged on a small rural town for a rare performance of the group that had been banned three years earlier for its weird music and bizarre stage antics. Suddenly battalions of police arrived and herded about 200 fans into a waiting railway car bound for Prague. "We never wanted to overthrow the regime," says the Plastic's founder, Milan Hlavsa. "We just wanted to make rock and roll."

But to the hard-line Czech authorities, anything that smacked of the West was a threat. Only last year were the remnants of the Plastic People finally granted official amateur status and allowed to plan a seven-city American tour. In Washington, Chicago, Boston and other U.S. cities, they've played to enthusiastic crowds of rock insiders and Czech expatriots who understand the band's historic role—and like its '60s-tinged music. "Pulnoc's songs have a defiant dignity that doesn't preclude dancing," wrote one critic.

Yet the long overdue appearance of Pulnoc (the name means midnight) wasn't entirely joyous. Only three of the original Plastic People—Hlavsa, now 38, keyboardist Josef Janicek, 42, and violist-guitarist Jiri Kabes, 43—endured to stand on an American stage. (Four new members have been added to the band.) Saxophonist Vratislav Brabenec, who was forced into exile in Canada in 1982, chose not to join his old comrades on tour. The Plastic People's one-time collaborator and artistic director, the poet Ivan Jirous, 44, is still languishing in a Czech prison, where he has spent eight of the last 15 years.

Milan Hlavsa, the son of a banker and a seamstress, formed the Plastic People in September 1968, shortly after Russian tanks rolled into Prague to crush the reformist government of Alexander Dub?ek. At first the band played songs by the Velvet Underground, the Fugs and the Doors under a banner that read JIM MORRISON IS OUR FATHER. In 1971 the government banned them and took away their instruments. Unfazed, the band went underground, playing at private parties with amplifiers that mechanic Janicek built out of old transistor radios. In this twilight world their music evolved into a homegrown psychedelic jazz-rock. In 1976, after playing at two underground music festivals, they were arrested.

"Six months in jail was not really jail," Hlavsa admits. "The prison guards were decent to us and brought us food. I gained 16 lbs." But the arrests became an international cause célèbre and helped prompt Czech intellectuals to form the human rights group Charter '77. The band members were freed but never granted official status. Still, they managed to perform occasionally and make several bootleg recordings while working in jobs such as stagehand, graphic designer and maintenance man.

Finally, in 1988, Hlavsa decided to regroup as Pulnoc and was granted amateur status. "We didn't make any compromises," says Kabes, sensitive to charges of selling out. "We were patient, we persisted. It's the crown of all our efforts now to see people enjoying our music."